02-Spring的IOC示例程序（通过id获取对象）

*******通过IOC容器创建id对象并为属性赋值********

整体结构：

①创建一个java工程

②导包

③创建log4j.properties日记配置文件

# Global logging configuration
log4j.rootLogger=INFO, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

④创建spring配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
　　***********此处是手写代码************
</beans>

⑤创建javaBean对象

package cn.aynu.pojo;

public class Person {
    private int id;
    private String name;
    private String phone;
    private int age;
    public Person() {
        super();
    }
    public Person(int id, String name, String phone, int age) {
        super();
        this.id = id;
        this.name = name;
        this.phone = phone;
        this.age = age;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Person [id=" + id + ", name=" + name + ", phone=" + phone + ", age=" + age + "]";
    }
    
}

⑥在application.xml中配置bean对象

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--id值（p1）不可重复，如果重复会报错，编译不通过 -->
<bean id="p1" class="cn.aynu.pojo.Person">
    <property name="id" value="1001"/>
    <property name="name" value="琥珀"/>
    <property name="phone" value="18337280000"/>
    <property name="age" value="18"/>
</bean>

</beans>

⑦写测试类（从容器中获取bean对象）

public class PersonTest {
    @Test
    public void Test01() {
        //获取spring容器对象(classpath:可略)
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext("classpath:application.xml");
        //根据id获取bean对象
        Person person = (Person) applicationContext.getBean("p1");
        System.out.println(person);
    }
}

 补充：①如果有多个对象同时获取P1，只有一次输出（单例模式）

　　　 ②优先调用无参构造器中的内容